This may be in the owners manual but since I don't have it handy I'll risk asking a stupid question........

How is the average mpg that's displayed on the dash calculated? Is it a running average from day one? If so the more miles you have when you make a change (tires, gears etc.) the longer it will take to see the change in mpg??? Or is it an average of the last X miles driven?

I recently re-geared (about 400 miles ago) and also re-programed for the tires. I have had 35s for nearly a year but just did the Procal so my avg mpg reading was about 11. Since reprograming and chAnging the gears (at same time) I am creeping up to 13mpg. Still a long. Ways off from what most folks on here report.

 

Anybody have an idea? I guess I will check mpg the old fashion way and compare to my dash reading. That should give me an idea of how close the " Avg Eco" reading is.

 

It is a rolling average unless you reset it. Fyi it will let you add correction factor if it is off.

 

Cool, where can I find an instructional on how?

 

I'm interested as well in how to reset and in the correction ability.

 

Whenever you do something snazzy to the jeep, just reset the ECO. To do this, you just get the left push button to the desired display, and then hold it down for about 3 seconds. It will reset to zero and start the ave calc from that point forward. I did this when I put on a new muffler. I did it again when I installed my superchip programmer.

 

I'd love to know how to correct it, as it is consistently 1 mpg off. Hand calculated is usually 17.7. Display usually is 18.6-.9. Speedometer is correct also.

 

That's where I am...12.8 to 13. And 13 doesn't last long. I can't get the 14 - 16 mpg I see reported by some folks even when I am coasting down a hill !!

I'm not complaining. It's not my DD and I knew what would happen when I added lift, larger tires, etc., etc.

 

My 2011 has the instructions in the owners manual

 

i get 9 fml